The connection between the metal shaft of a wind tower and the foundation where said shaft is supported is usually carried out by means of an active reinforcement, made up of steel bars or pins embedded in the foundation. These bars or pins are intended for fitting into holes of mounting flanges comprised in the shaft. Therefore, said bars or pins must be installed with a great mounting precision, because otherwise the flange of the metal shaft will not be able to be threaded through same. This operation takes up a lot of mounting times, in addition to requiring significant auxiliary means which allow installing said bars with suitable tolerances of millimeters. Said auxiliary means comprise installing annular templates which allow mounting and installing said system of bars.
On the other hand, this system makes it necessary to drill the mounting flanges comprised in the shafts, thereby weakening their bearing capacity and increasing their price.
There are designs of connection systems between the foundation and the shaft, the only difference of which lies in the type of active reinforcement to be used. In other words, instead of steel bars or pins, tendons of unbonded strand are used. These designs make threading of the steel shaft on the mounting flange easier since the system of non-adherent strand is somehow more flexible, but it does not solve the problem since mounting tolerances of millimeters is still required and furthermore, the flexibility which is favorable in certain form to be able to adjust the position of the standby reinforcement, in this case strands, becomes unfavorable since the position of said standby strands is not always the same. This makes it necessary to use auxiliary mounting systems to be able to suitably install the non-adherent strands.
The present invention describes a connection system preventing the mentioned drawbacks, providing a connection between the shaft of the wind tower and the surface supporting it that is easier to mount than the earlier solutions as it is less sensitive to geometrical errors, in turn complying with the suitable tolerances. Additionally, the service life of said connection also increases.